The present invention relates to sockets that electrically connects an integrated circuit with an IC board. More particularly, the present invention is directed to a backing plate for such a socket, used to ship the sockets and protect them from damage, and also includes specially designed grooves for cutting elastomer components of the test socket, allowing precise fitting of the elastomers for use with such sockets.
Integrated circuit tester devices have long been used in the semiconductor industry to test and evaluate the quality of the chips off the manufacturing line. Signal integrity is a critical aspect of chip design and testing. To this end, it is desirable to maintain impedance through a conducting portion of a contact interconnecting the integrated circuit lead to its corresponding load board pad at a particular desired level. The effective impedance of the design is a function of a number of factors. These include width and length of conduction path, material of which the conductive structure is made, material thickness, etc.
When testing the electrical characteristics of a packaged or molded semiconductor device such as an integrated circuit (IC), it is common to utilize a specialized test socket that secures and connects the IC to the equipment that evaluates its performance, i.e. a load board. Many different test sockets have been devised for quickly and temporarily connecting integrated circuit leads of a chip to be tested to a load board of a tester. Automated test apparatus in particular use a number of such sockets. Typical socket arrangements use force brought to bear upon a contact positioned between a lead of the IC and the load board to deform a probe tip of the contact and engage a pad on the load board. Such a configuration provides for positive connection between the pins or contact pads of the DUT and corresponding leads of a test apparatus. Examples of this type of connection can be found, for example, in U.S. Pat. No. 6,409,521 to Rathburn, and U.S. Pat. No. 7,737,708 to Sherry, the teachings and contents of both of which are fully incorporated herein by reference.
U.S. Pat. No. 7,918,669, the contents of which are incorporated herein by reference, is a test socket devised by the present inventor. The socket of the '669 patent uses a unique linkage to urge the connectors of the test circuit upward where it can make contact with the test equipment. This test socket was found to be very successful in ensuring good contact with the test apparatus while reducing force on the circuit itself. A component of that test socket was an elastomer element that provided a resiliency to the link, ensuring proper contact in a cost effective and reliable manner. The cylindrical elastomer keeps the contact links in place, and their resiliency acts like a spring mechanism for the links. This allows for vertical movement on the link.
When such test sockets are shipped, they are accompanied by a shipping back plate, or socket mount, that is essentially a protective structure created to hold the socket in place. This socket mount contains fastener holes on the outside corresponding to the holes on the socket, so that the screw and pins can go through the back plate and the socket can sit flush. These back plates are either discarded once the socket is received by the user, or reused in some cases. The Applicant of the present invention has devised a secondary use for the socket mount, which is particular to the test socket of the '669 patent.